drm/i915: Simplify relocate_entry_gtt() and make 64-bit safe

Even though we should not try to use 4+GiB GTTs on 32-bit systems, by
using a local variable we can future proof the code whilst making it
easier to read.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: Appease checkpatch a bit.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 6c07940..dec2cc2 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -293,7 +293,7 @@ relocate_entry_gtt(struct drm_i915_gem_object *obj,
        struct drm_device *dev = obj->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        uint64_t delta = reloc->delta + target_offset;
-       uint32_t __iomem *reloc_entry;
+       uint64_t offset;
        void __iomem *reloc_page;
        int ret;
 
@@ -306,25 +306,24 @@ relocate_entry_gtt(struct drm_i915_gem_object *obj,
                return ret;
 
        /* Map the page containing the relocation we're going to perform.  */
-       reloc->offset += i915_gem_obj_ggtt_offset(obj);
+       offset = i915_gem_obj_ggtt_offset(obj);
+       offset += reloc->offset;
        reloc_page = io_mapping_map_atomic_wc(dev_priv->gtt.mappable,
-                       reloc->offset & PAGE_MASK);
-       reloc_entry = (uint32_t __iomem *)
-               (reloc_page + offset_in_page(reloc->offset));
-       iowrite32(lower_32_bits(delta), reloc_entry);
+                                             offset & PAGE_MASK);
+       iowrite32(lower_32_bits(delta), reloc_page + offset_in_page(offset));
 
        if (INTEL_INFO(dev)->gen >= 8) {
-               reloc_entry += 1;
+               offset += sizeof(uint32_t);
 
-               if (offset_in_page(reloc->offset + sizeof(uint32_t)) == 0) {
+               if (offset_in_page(offset) == 0) {
                        io_mapping_unmap_atomic(reloc_page);
-                       reloc_page = io_mapping_map_atomic_wc(
-                                       dev_priv->gtt.mappable,
-                                       reloc->offset + sizeof(uint32_t));
-                       reloc_entry = reloc_page;
+                       reloc_page =
+                               io_mapping_map_atomic_wc(dev_priv->gtt.mappable,
+                                                        offset);
                }
 
-               iowrite32(upper_32_bits(delta), reloc_entry);
+               iowrite32(upper_32_bits(delta),
+                         reloc_page + offset_in_page(offset));
        }
 
        io_mapping_unmap_atomic(reloc_page);